A conventional scroll compressor comprises, as shown in FIG. 6, a rear casing 32 having an opening at the front side, and a front cover 31 placed in its opening. A movable scroll 34, a fixed scroll 39, and a rotation preventive mechanism 36 are disposed in the rear casing 32. An outer circumference of the fixed scroll 39 contacts with an inner circumference of the rear casing 32. The movable scroll 34 is placed between the front cover 31 and the fixed scroll 39 in order to swivel while contacting with the surface of the fixed scroll 39. The rotation preventive mechanism 36 is placed between the movable scroll 34 and the front cover 31 in order to allow the swivel motion only while preventing rotation of the movable scroll 34. A suction chamber 46 for sucking a refrigerant and a discharge chamber 47 for discharging the refrigerant are mutually partitioned through the fixed scroll 39. A suction port 32c for sucking the refrigerant is formed in an outer wall of the rear casing 32 of the suction chamber 46. A discharge port 32d for discharging the refrigerant is formed in the outer wall of the rear casing 32 of the discharge chamber 47. A first seal member 41 having an O-ring 41 is placed between the inner circumference 32a of the rear casing 32 and the fixed scroll 39. This first seal member 41 seals between the fixed scroll 39 and the rear casing 32. It is thus completely sealed between the suction chamber 46 and discharge chamber 47.
A plurality of mounting bases 32b for mounting on a vehicle or other mechanical structure are integrally disposed on the outer wall of the rear casing 32. The front cover 31 has a clutch mounting section 31c. A shaft 40 is installed so as to cooperate with the movable scroll 34, and this shaft 40 penetrates through the clutch mounting section 31 c, and has its leading end exposed outside. An electromagnetic clutch 38 is installed outside of the clutch mounting section 31c, and is coupled to the shaft 40. The front cover 31 is coupled to the rear casing 32 through a second seal member 45, by using bolt 44 or other bonding member. The second seal member 45 seals between the front cover 31 and rear casing 32, and by this seal member 45, the suction chamber 46 and the outside are completely isolated. Thus, a pressure vessel sealing mutually between the suction pressure and atmospheric pressure was constituted by using the first seal member 41 and second seal member 45.
In such conventional compressor, however, the rear casing cover 32 is manufactured separately from the front cover 31, and the rear casing 32 and front cover 31 are coupled through the second seal member when assembling by using bolt 44 or other coupling member. Further, mounting bases 32b are integrally formed in the rear casing 32, and a movable scroll 34 and a shaft 40 linked to the electromagnetic clutch are fitted to the front cover 31. Thus, the member and bases 32b for fixing the shaft 40 are mutually fitted to different parts.
Accordingly, when the compressor is mounted on the apparatus, it is required to match accurately the precision of mutual positions of the outer member and bases 32b coupled to the shaft 40, and the mounting work was complicated.